2017-10-17 2:12 GMT+09:00 Douglas Anderson <dianders@xxxxxxxxxxxx>: > This two-patch series attempts to speed incremental builds of the > kernel up by a bit. How much of a speedup you get depends a lot on > your environment, specifically the speed of your workstation and how > fast it takes to invoke the compiler. > > In the Chrome OS build environment you get a really big win. For an > incremental build (via emerge) I measured a speedup from ~1 minute to > ~35 seconds. ...but Chrome OS calls the compiler through a number of > wrapper scripts and also calls the kernel make at least twice for an > emerge (during compile stage and install stage), so it's a bit of a > worst case. > > Perhaps a more realistic measure of the speedup others might see is > running "time make help > /dev/null" outside of the Chrome OS build > environment on my system. When I do this I see that it took more than > 1.0 seconds before and less than 0.2 seconds after. So presumably > this has the ability to shave ~0.8 seconds off an incremental build > for most folks out there. While 0.8 seconds savings isn't huge, it > does make incremental builds feel a lot snappier. > > Ingo Molnar also did some testing of this in his environment and found > that an incremental build of his subsystem sped up from ~.44 seconds > before to ~.15 seconds after. Clean builds also sped up by a marginal > amount. :) > > Changes in v4: > - Add a mkdir > - Point to forward declaration commit by git hash > > Changes in v3: > - Rule to prevent make from trying to generate the cache > - Rule to clean .cache.mk > - No more doc changes > - Moved cache stuff below cc-cross-prefix > - Removed duplicate documentation of try-run (oops) > - Add Tested-by for Ingo and Guenter since v2 and v3 are very similar > > Changes in v2: > - Abstract at a different level (like shell-cached) per Masahiro Yamada > - Include ld-version, which I missed the first time > > Douglas Anderson (2): > kbuild: Add a cache for generated variables > kbuild: Cache a few more calls to the compiler > > Makefile | 5 +-- > scripts/Kbuild.include | 90 ++++++++++++++++++++++++++++++++++++++++++-------- > 2 files changed, 79 insertions(+), 16 deletions(-) > Applied to linux-kbuild/kbuild. Thanks. -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
